1. Field of the Invention
The present invention relates to a printed board designing apparatus, a printed board designing method and a control program for printed board design, and more particularly to a printed board designing apparatus and a printed board designing method suitable for use to design a printed board for a circuit in which a plurality of signals of different high frequencies flow and a recording medium on which a control program for printed board design is recorded.
2. Description of the Related Art
In design of a printed board, properties, materials and shapes are selected in accordance with a performance or a mounting method of an electronic equipment, and in recent years, the demanded level for them has become higher in order to increase the density of wiring lines and increase the number of layers. As a result of the increase of the density of wiring lines, printed boards having a pattern width smaller than 0.1 mm have been put into practical use while assuring a sectional area of a pattern. The distance between patterns depends upon a material used, whether or not a coating is present and an applied voltage. In a multilayer printed board, also it is important to examine the gap between a through-hole and an adjacent pattern. As other electric properties, the electric capacity, the characteristic impedance and the crosstalk are taken into consideration to design a pattern or determine a layer configuration of multiple layers, and a printed board is designed based on the determined details by a printed board designing apparatus.
A printed board designing apparatus of the type mentioned is disclosed, for example, in Japanese Patent Laid-Open No. 312176/1992. FIG. 7 illustrates wiring line information of a circuit diagram used in the printed board designing apparatus disclosed in the document.
Referring to FIG. 7, pins xe2x80x9cA1xe2x80x9d, xe2x80x9cA2xe2x80x9d, xe2x80x9cA3xe2x80x9d, xe2x80x9cA4xe2x80x9d, xe2x80x9cA5xe2x80x9d and xe2x80x9cA6xe2x80x9d of a connector 2 are connected to input/output pins xe2x80x9c1xe2x80x9d, xe2x80x9c2xe2x80x9d, xe2x80x9c3xe2x80x9d, xe2x80x9c4xe2x80x9d, xe2x80x9c5xe2x80x9d and xe2x80x9c6xe2x80x9d of an integrated circuit (hereinafter referred to simply as xe2x80x9cICxe2x80x9d) 1. To a signal line between the input/output pin xe2x80x9c1xe2x80x9d and the pin xe2x80x9cA1xe2x80x9d, a signal name xe2x80x9csignal 1xe2x80x9d and a voltage identification symbol xe2x80x9cExe2x80x9d (xe2x80x9cExe2x80x9d denotes a ground (earth) line) are applied. To a signal line between the input/output pin xe2x80x9c2xe2x80x9d and the pin xe2x80x9cA2xe2x80x9d, a signal name xe2x80x9csignal 2xe2x80x9d and a voltage identification symbol xe2x80x9c5xe2x80x9d (xe2x80x9c5xe2x80x9d denotes a +5 V line) are applied. To a signal line between the input/output pin xe2x80x9c3xe2x80x9d and the pin xe2x80x9cA3xe2x80x9d, a signal name xe2x80x9csignal 3xe2x80x9d and a voltage identification symbol xe2x80x9cSxe2x80x9d (xe2x80x9cSxe2x80x9d denotes a signal line) are applied. To a signal line between the input/output pin xe2x80x9c4xe2x80x9d and the pin xe2x80x9cA4xe2x80x9d, a signal name xe2x80x9csignal 4xe2x80x9d and a voltage identification symbol xe2x80x9cSxe2x80x9d are applied. To a signal line between the input/output pin xe2x80x9c5xe2x80x9d and the pin xe2x80x9cA5xe2x80x9d, a signal name xe2x80x9csignal 6xe2x80x9d and a voltage identification symbol xe2x80x9cM48xe2x80x9d (xe2x80x9cM48xe2x80x9d denotes a xe2x88x9248V line) are applied.
FIG. 8 shows a pattern of a printed board produced based on the wiring line information of FI. 7 by the printed board designing apparatus described above.
Referring to FIG. 8, respective patterns are formed between the input/output pins xe2x80x9c1xe2x80x9d, xe2x80x9c2xe2x80x9d, xe2x80x9c3xe2x80x9d, xe2x80x9c4xe2x80x9d, xe2x80x9c5xe2x80x9d and xe2x80x9c6xe2x80x9d and the pins xe2x80x9cA1xe2x80x9d, xe2x80x9cA2xe2x80x9d, xe2x80x9cA3xe2x80x9d, xe2x80x9cA4xe2x80x9d, xe2x80x9cA5xe2x80x9d and xe2x80x9cA6xe2x80x9d on a printed board 3 shown based on the wiring line information of FIG. 7. In this instance, a potential difference between those patterns which are positioned adjacent each other upon wiring, for example, between the patterns 4 and 5, is calculated using the voltage identification symbols xe2x80x9cExe2x80x9d, xe2x80x9c5xe2x80x9d, xe2x80x9cSxe2x80x9d, xe2x80x9cSxe2x80x9d, xe2x80x9cGxe2x80x9d and xe2x80x9cM48xe2x80x9d, and a gap D necessary for prevention of crosstalk is provided based on the potential difference. Further, where a different pattern 6 is formed on the rear face of the printed board 3 such that it intersects with any other pattern formed already, a potential difference between the layers at the portion at which the patterns intersect with each other as viewed in a see-through fashion is calculated, and a gap necessary for prevention of crosstalk is provided based on the thus calculated potential difference.
However, the conventional printed board designing apparatus described above has the following problem.
In particular, according to the conventional printed board designing apparatus, crosstalk in the printed board 3 shown in FIG. 8 is prevented through the provision of a gap based on a potential difference between each adjacent patterns. However, in a printed board in the inside of an electronic equipment in recent years, various signals having higher frequencies than ever flow, and therefore, there is a problem that provision only of a gap provided based on a potential difference between each adjacent patterns cannot sufficiently prevent the crosstalk. Therefore, it is necessary to investigate prevention of crosstalk with regard to various signals of high frequencies in the stage of designing of a printed board.
It is an object of the present invention to provide a printed board designing apparatus, a printed board designing method and a recording medium having a control program for printed board design recorded thereon by which a printed circuit board which prevents occurrence of crosstalk with regard to various signals of high frequencies can be prevented.
In order to attain the object described above, according to an aspect of the present invention, there is provided a printed board designing apparatus for receiving a circuit diagram corresponding to information of wiring lines of a circuit and designing patterns corresponding to the individual wiring lines of the circuit diagram, comprising crosstalk occurrence discrimination means for comparing signals to flow in the patterns with each other in terms of a characteristic and discriminating occurrence of crosstalk when the signals are different from each other in terms of the characteristic, and display means for displaying the designed patterns and displaying a predetermined mark at a location of the display of the design patterns at which the crosstalk occurs.
The crosstalk occurrence discrimination means may comparing signals to flow in each two adjacent ones of the patterns with each other in terms of a voltage, a type and a frequency as the characteristic and discriminate occurrence of crosstalk when the signals are different from each other in terms of at least one of the factors of the voltage, type and frequency.
According to another aspect of the present invention, there is provided a printed board designing apparatus, comprising circuit diagram inputting means for inputting a circuit diagram corresponding to information of wiring lines of a circuit and applying, to each of the wiring lines in the circuit diagram, signal name data representative of a characteristic of a signal to flow in the wiring line, pattern designing means for designing patterns corresponding to the wiring lines based on the circuit diagram and applying the pertaining signal name data to the designed patterns, crosstalk occurrence discrimination means for comparing the signal name data corresponding to each two adjacent ones of the patterns and discriminating occurrence of crosstalk when the signal name data represent signals whose characteristics are different from each other, and display means for displaying the designed patterns and displaying a predetermined mark at a location of the display of the design patterns at which the crosstalk occurs.
According to a further aspect of the present invention, there is provided a printed board designing apparatus, comprising circuit diagram inputting means for inputting a circuit diagram corresponding to information of wiring lines of a circuit and applying, to each of the wiring lines in the circuit diagram, signal name data representative of a voltage, a type and a frequency of a signal to flow in the wiring line, pattern designing means for designing patterns corresponding to the wiring lines based on the circuit diagram and applying the pertaining signal name data to the designed patterns, crosstalk occurrence discrimination means for comparing the signal name data corresponding to each two adjacent ones of the patterns in terms of the voltage, type and frequency and discriminating occurrence of crosstalk when the signals are different from each other in terms of at least one of the voltage, type and frequency, and display means for displaying the designed patterns and the signal name data and displaying a predetermined mark at a location of the display of the design patterns at which the crosstalk occurs.
According to a still further aspect of the present invention, there is provided a printed board designing method for a printed board designing apparatus which receives a circuit diagram corresponding to information of wiring lines of a circuit and designs patterns corresponding to the individual wiring lines of the circuit diagram, comprising a crosstalk occurrence discrimination step of comparing signals to flow in the patterns with each other in terms of a characteristic and discriminating occurrence of crosstalk when the signals are different from each other in terms of the characteristic, and a displaying step of displaying the designed patterns and displaying a predetermined mark at a location of the display of the design patterns at which the crosstalk occurs.
In the crosstalk occurrence discrimination step, signals to flow in each two adjacent ones of the patterns may be with each other in terms of a voltage, a type and a frequency as the characteristic and occurrence of crosstalk may be discriminated when the signals are different from each other in terms of at least one of the factors of the voltage, type and frequency.
According to a yet further aspect of the present invention, there is provided a printed board designing method for a printed board designing apparatus, comprising a circuit diagram inputting step of inputting a circuit diagram corresponding to information of wiring lines of a circuit and applying, to each of the wiring lines in the circuit diagram, signal name data representative of a characteristic of a signal to flow in the wiring line, a pattern designing step of designing patterns corresponding to the wiring lines based on the circuit diagram and applying the pertaining signal name data to the designed patterns, a crosstalk occurrence discrimination step of comparing the signal name data corresponding to each two adjacent ones of the patterns and discriminating occurrence of crosstalk when the signal name data represent signals whose characteristics are different from each other, and a displaying step of displaying the designed patterns and displaying a predetermined mark at a location of the display of the design patterns at which the crosstalk occurs.
According to a yet further aspect of the present invention, there is provided a printed board designing method for a printed board designing apparatus, comprising a circuit diagram inputting step of inputting a circuit diagram corresponding to information of wiring lines of a circuit and applying, to each of the wiring lines in the circuit diagram, signal name data representative of a voltage, a type and a frequency of a signal to flow in the wiring line, a pattern designing step of designing patterns corresponding to the wiring lines based on the circuit diagram and applying the pertaining signal name data to the designed patterns, a crosstalk occurrence discrimination step of comparing the signal name data corresponding to each two adjacent ones of the patterns in terms of the voltage, type and frequency and discriminating occurrence of crosstalk when the signals are different from each other in terms of at least one of the voltage, type and frequency, and a displaying step of displaying the designed patterns and the signal name data and displaying a predetermined mark at a location of the display of the design patterns at which the crosstalk occurs.
According to a yet further aspect of the present invention, there is provided a recording medium on which a control program for a printed board designing apparatus which receives a circuit diagram corresponding to information of wiring lines of a circuit and designs patterns corresponding to the individual wiring lines of the circuit diagram is recorded, the control program comprising the steps of any of the printed board designing method for a printed board designing apparatus recited as above.
With the printed board designing apparatus, printed board designing method and recording medium, since the crosstalk occurrence discrimination means compares signals to flow in each two adjacent ones of patterns in terms of the voltage, type and frequency and discriminates occurrence of crosstalk when the signals are different from each other in at least one of the factors of the voltage, type and frequency and then the display means displays the predetermined mark representing the crosstalk, a printed board which prevents possible occurrence of crosstalk in a circuit in which various signals of high frequencies flow can be designed.
The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings in which like parts or elements are denoted by like reference symbols.